In recent years, as audio/visual (AV) devices using digital signals, such as audio signals or video signals, become widespread, various types of interfaces have been proposed as interfaces for transmitting digital signals between these AV devices. For example, as such interfaces, the Institute of Electrical and Electronics Engineers (IEEE) 1394 standards, the High-Definition Multimedia Interface (HDMI) standards (HDMI is a registered trademark), and the like, are widely known (for example, see JP-A-2007-267116 (FIG. 1)).
Furthermore, for a comparatively large-scale system, an interface for distributing digital signals by using Ethernet™ has also been proposed (for example, see JP-T-2003-523653 (FIGS. 6A and 6B)).